Magnetic disks include inherent defects. In order to prevent defect locations from being assigned to a user area, conventionally, defect locations are identified prior to shipment of hard disk devices. The defects identified before shipment can be referred to as primary defects.
The primary-defect locations are set as non-usable and not assigned to the user area. As an example, the assignment of logical addresses to primary-defect locations is inhibited. A reduced capacity of a magnetic disk due to the non-use of primary-defect locations can be compensated for by a redundant area prepared in the magnetic disk.